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38 * Implements gmx::HardwareTopology.
40 * \author Erik Lindahl <erik.lindahl@gmail.com>
41 * \ingroup module_hardware
46 #include "hardwaretopology.h"
62 #include "gromacs/hardware/cpuinfo.h"
63 #include "gromacs/utility/gmxassert.h"
66 # include <unistd.h> // sysconf()
68 #if GMX_NATIVE_WINDOWS
69 # include <windows.h> // GetSystemInfo()
72 //! Convenience macro to help us avoid ifdefs each time we use sysconf
73 #if !defined(_SC_NPROCESSORS_ONLN) && defined(_SC_NPROC_ONLN)
74 # define _SC_NPROCESSORS_ONLN _SC_NPROC_ONLN
83 /*****************************************************************************
85 * Utility functions for extracting hardware topology from CpuInfo object *
87 *****************************************************************************/
89 /*! \brief Initialize machine data from basic information in cpuinfo
91 * \param machine Machine tree structure where information will be assigned
92 * if the cpuinfo object contains topology information.
93 * \param supportLevel If topology information is available in CpuInfo,
94 * this will be updated to reflect the amount of
95 * information written to the machine structure.
98 parseCpuInfo(HardwareTopology::Machine * machine,
99 HardwareTopology::SupportLevel * supportLevel)
101 CpuInfo cpuInfo(CpuInfo::detect());
103 if (!cpuInfo.logicalProcessors().empty())
109 // Copy the logical processor information from cpuinfo
110 for (auto &l : cpuInfo.logicalProcessors())
112 machine->logicalProcessors.push_back( { l.socketRankInMachine, l.coreRankInSocket, l.hwThreadRankInCore, -1 } );
113 nSockets = std::max(nSockets, l.socketRankInMachine);
114 nCores = std::max(nCores, l.coreRankInSocket);
115 nHwThreads = std::max(nHwThreads, l.hwThreadRankInCore);
118 // Fill info form sockets/cores/hwthreads
123 machine->sockets.resize(nSockets + 1);
124 for (auto &s : machine->sockets)
127 s.cores.resize(nCores + 1);
128 for (auto &c : s.cores)
131 c.numaNodeId = -1; // No numa information
132 c.hwThreads.resize(nHwThreads + 1);
133 for (auto &t : c.hwThreads)
136 t.logicalProcessorId = -1; // set as unassigned for now
141 // Fill the logical processor id in the right place
142 for (std::size_t i = 0; i < machine->logicalProcessors.size(); i++)
144 const HardwareTopology::LogicalProcessor &l = machine->logicalProcessors[i];
145 machine->sockets[l.socketRankInMachine].cores[l.coreRankInSocket].hwThreads[l.hwThreadRankInCore].logicalProcessorId = static_cast<int>(i);
147 machine->logicalProcessorCount = machine->logicalProcessors.size();
148 *supportLevel = HardwareTopology::SupportLevel::Basic;
152 *supportLevel = HardwareTopology::SupportLevel::None;
158 #if HWLOC_API_VERSION < 0x00010b00
159 # define HWLOC_OBJ_PACKAGE HWLOC_OBJ_SOCKET
160 # define HWLOC_OBJ_NUMANODE HWLOC_OBJ_NODE
163 // Preprocessor variable for if hwloc api is version 1.x.x or 2.x.x
164 #if HWLOC_API_VERSION >= 0x00020000
165 # define GMX_HWLOC_API_VERSION_IS_2XX 1
167 # define GMX_HWLOC_API_VERSION_IS_2XX 0
170 /*****************************************************************************
172 * Utility functions for extracting hardware topology from hwloc library *
174 *****************************************************************************/
176 // Compatibility function for accessing hwloc_obj_t object memory with different API versions of hwloc
178 getHwLocObjectMemory(const hwloc_obj* obj)
180 #if GMX_HWLOC_API_VERSION_IS_2XX
181 return obj->total_memory;
183 return obj->memory.total_memory;
187 /*! \brief Return vector of all descendants of a given type in hwloc topology
189 * \param topo hwloc topology handle that has been initialized and loaded
190 * \param obj Non-null hwloc object.
191 * \param type hwloc object type to find. The routine will only search
192 * on levels below obj.
194 * \return vector containing all the objects of given type that are
195 * descendants of the provided object. If no objects of this type
196 * were found, the vector will be empty.
198 const std::vector<const hwloc_obj*>
199 getHwLocDescendantsByType(const hwloc_topology* topo, const hwloc_obj* obj, const hwloc_obj_type_t type)
201 GMX_RELEASE_ASSERT(obj, "NULL hwloc object provided to getHwLocDescendantsByType()");
203 std::vector<const hwloc_obj*> v;
205 if (obj->type == type)
209 // Go through children; if this object has no children obj->arity is 0,
210 // and we'll return an empty vector.
211 hwloc_obj_t tempNode = nullptr;
212 while ((tempNode = hwloc_get_next_child(const_cast<hwloc_topology_t>(topo),
213 const_cast<hwloc_obj_t>(obj),
214 tempNode)) != nullptr)
216 std::vector<const hwloc_obj*> v2 = getHwLocDescendantsByType(topo, tempNode, type);
217 v.insert(v.end(), v2.begin(), v2.end());
222 /*! \brief Read information about sockets, cores and threads from hwloc topology
224 * \param topo hwloc topology handle that has been initialized and loaded
225 * \param machine Pointer to the machine structure in the HardwareTopology
226 * class, where the tree of sockets/cores/threads will be written.
228 * \return If all the data is found
231 parseHwLocSocketsCoresThreads(hwloc_topology_t topo,
232 HardwareTopology::Machine * machine)
234 const hwloc_obj* root = hwloc_get_root_obj(topo);
235 std::vector<const hwloc_obj*> hwlocSockets = getHwLocDescendantsByType(topo, root, HWLOC_OBJ_PACKAGE);
237 machine->logicalProcessorCount = hwloc_get_nbobjs_by_type(topo, HWLOC_OBJ_PU);
238 machine->logicalProcessors.resize(machine->logicalProcessorCount);
239 machine->sockets.resize(hwlocSockets.size());
241 bool topologyOk = !hwlocSockets.empty(); // Fail if we have no sockets in machine
243 for (std::size_t i = 0; i < hwlocSockets.size() && topologyOk; i++)
245 // Assign information about this socket
246 machine->sockets[i].id = hwlocSockets[i]->logical_index;
248 // Get children (cores)
249 std::vector<const hwloc_obj*> hwlocCores = getHwLocDescendantsByType(topo, hwlocSockets[i], HWLOC_OBJ_CORE);
250 machine->sockets[i].cores.resize(hwlocCores.size());
252 topologyOk = topologyOk && !hwlocCores.empty(); // Fail if we have no cores in socket
254 // Loop over child cores
255 for (std::size_t j = 0; j < hwlocCores.size() && topologyOk; j++)
257 // Assign information about this core
258 machine->sockets[i].cores[j].id = hwlocCores[j]->logical_index;
259 machine->sockets[i].cores[j].numaNodeId = -1;
261 // Get children (hwthreads)
262 std::vector<const hwloc_obj*> hwlocPUs = getHwLocDescendantsByType(topo, hwlocCores[j], HWLOC_OBJ_PU);
263 machine->sockets[i].cores[j].hwThreads.resize(hwlocPUs.size());
265 topologyOk = topologyOk && !hwlocPUs.empty(); // Fail if we have no hwthreads in core
267 // Loop over child hwthreads
268 for (std::size_t k = 0; k < hwlocPUs.size() && topologyOk; k++)
270 // Assign information about this hwthread
271 std::size_t logicalProcessorId = hwlocPUs[k]->os_index;
272 machine->sockets[i].cores[j].hwThreads[k].id = hwlocPUs[k]->logical_index;
273 machine->sockets[i].cores[j].hwThreads[k].logicalProcessorId = logicalProcessorId;
275 if (logicalProcessorId < machine->logicalProcessors.size())
277 // Cross-assign data for this hwthread to the logicalprocess vector
278 machine->logicalProcessors[logicalProcessorId].socketRankInMachine = static_cast<int>(i);
279 machine->logicalProcessors[logicalProcessorId].coreRankInSocket = static_cast<int>(j);
280 machine->logicalProcessors[logicalProcessorId].hwThreadRankInCore = static_cast<int>(k);
281 machine->logicalProcessors[logicalProcessorId].numaNodeId = -1;
293 machine->logicalProcessors.clear();
294 machine->sockets.clear();
299 /*! \brief Read cache information from hwloc topology
301 * \param topo hwloc topology handle that has been initialized and loaded
302 * \param machine Pointer to the machine structure in the HardwareTopology
303 * class, where cache data will be filled.
305 * \return If any cache data is found
308 parseHwLocCache(hwloc_topology_t topo,
309 HardwareTopology::Machine * machine)
311 // Parse caches up to L5
312 for (int cachelevel : { 1, 2, 3, 4, 5})
314 int depth = hwloc_get_cache_type_depth(topo, cachelevel, HWLOC_OBJ_CACHE_DATA);
318 hwloc_obj_t cache = hwloc_get_next_obj_by_depth(topo, depth, nullptr);
319 if (cache != nullptr)
321 std::vector<const hwloc_obj*> hwThreads = getHwLocDescendantsByType(topo, cache, HWLOC_OBJ_PU);
323 machine->caches.push_back( {
324 static_cast<int>(cache->attr->cache.depth),
325 static_cast<std::size_t>(cache->attr->cache.size),
326 static_cast<int>(cache->attr->cache.linesize),
327 static_cast<int>(cache->attr->cache.associativity),
328 std::max<int>(hwThreads.size(), 1)
333 return !machine->caches.empty();
337 /*! \brief Read numa information from hwloc topology
339 * \param topo hwloc topology handle that has been initialized and loaded
340 * \param machine Pointer to the machine structure in the HardwareTopology
341 * class, where numa information will be filled.
343 * Hwloc should virtually always be able to detect numa information, but if
344 * there is only a single numa node in the system it is not reported at all.
345 * In this case we create a single numa node covering all cores.
347 * This function uses the basic socket/core/thread information detected by
348 * parseHwLocSocketsCoresThreads(), which means that routine must have
349 * completed successfully before calling this one. If this is not the case,
350 * you will get an error return code.
352 * \return If the data found makes sense (either in the numa node or the
356 parseHwLocNuma(hwloc_topology_t topo,
357 HardwareTopology::Machine * machine)
359 const hwloc_obj* root = hwloc_get_root_obj(topo);
360 std::vector<const hwloc_obj*> hwlocNumaNodes = getHwLocDescendantsByType(topo, root, HWLOC_OBJ_NUMANODE);
361 bool topologyOk = true;
363 if (!hwlocNumaNodes.empty())
365 machine->numa.nodes.resize(hwlocNumaNodes.size());
367 for (std::size_t i = 0; i < hwlocNumaNodes.size(); i++)
369 machine->numa.nodes[i].id = hwlocNumaNodes[i]->logical_index;
370 machine->numa.nodes[i].memory = getHwLocObjectMemory(hwlocNumaNodes[i]);;
371 machine->numa.nodes[i].logicalProcessorId.clear();
373 // Get list of PUs in this numa node. Get from numa node if v1.x.x, get from numa node's parent if 2.x.x
374 #if GMX_HWLOC_API_VERSION_IS_2XX
375 std::vector<const hwloc_obj*> hwlocPUs = getHwLocDescendantsByType(topo, hwlocNumaNodes[i]->parent, HWLOC_OBJ_PU);
377 std::vector<const hwloc_obj*> hwlocPUs = getHwLocDescendantsByType(topo, hwlocNumaNodes[i], HWLOC_OBJ_PU);
379 for (auto &p : hwlocPUs)
381 machine->numa.nodes[i].logicalProcessorId.push_back(p->os_index);
383 GMX_RELEASE_ASSERT(p->os_index < machine->logicalProcessors.size(), "OS index of PU in hwloc larger than processor count");
385 machine->logicalProcessors[p->os_index].numaNodeId = static_cast<int>(i);
386 std::size_t s = machine->logicalProcessors[p->os_index].socketRankInMachine;
387 std::size_t c = machine->logicalProcessors[p->os_index].coreRankInSocket;
389 GMX_RELEASE_ASSERT(s < machine->sockets.size(), "Socket index in logicalProcessors larger than socket count");
390 GMX_RELEASE_ASSERT(c < machine->sockets[s].cores.size(), "Core index in logicalProcessors larger than core count");
391 // Set numaNodeId in core too
392 machine->sockets[s].cores[c].numaNodeId = i;
395 // Getting the distance matrix
396 #if GMX_HWLOC_API_VERSION_IS_2XX
397 // with hwloc api v. 2.x.x, distances are no longer directly accessible. Need to retrieve and release hwloc_distances_s object
398 // In addition, there can now be multiple types of distances, ie latency, bandwidth. We look only for latency, but have to check
399 // if multiple distance matrices are returned.
401 // If only 1 numa node exists, the v2.x.x hwloc api won't have a distances matrix, set manually
402 if (hwlocNumaNodes.size() == 1)
404 machine->numa.relativeLatency = { { 1.0 } };
408 hwloc_distances_s* dist;
409 // Set the number of distance matrices to return (1 in our case, but hwloc 2.x.x allows
410 // for multiple distances types and therefore multiple distance matrices)
412 hwloc_distances_get(topo, &nr, &dist, HWLOC_DISTANCES_KIND_MEANS_LATENCY, 0);
413 // If no distances were found, nr will be 0, otherwise distances will be populated with 1
414 // hwloc_distances_s object
415 if (nr > 0 && dist->nbobjs == hwlocNumaNodes.size())
418 machine->numa.relativeLatency.resize(dist->nbobjs);
419 for (std::size_t i = 0; i < dist->nbobjs; i++)
421 machine->numa.relativeLatency[i].resize(dist->nbobjs);
422 for (std::size_t j = 0; j < dist->nbobjs; j++)
424 machine->numa.relativeLatency[i][j] = dist->values[i*dist->nbobjs+j];
432 hwloc_distances_release(topo, dist);
435 // hwloc-2.x provides latencies as integers, but to make things more similar to the case of a single
436 // numa node as well as hwloc-1.x, we rescale to relative floating-point values and also set the
437 // largest relative latency value.
439 // find smallest value in matrix
440 float minLatency = std::numeric_limits<float>::max(); // large number
441 float maxLatency = std::numeric_limits<float>::min(); // 0.0
442 for (const auto &v : machine->numa.relativeLatency)
444 auto result = std::minmax_element(v.begin(), v.end());
445 minLatency = std::min(minLatency, *result.first);
446 maxLatency = std::max(maxLatency, *result.second);
450 for (auto &v : machine->numa.relativeLatency)
452 std::transform(v.begin(), v.end(), v.begin(), std::bind(std::multiplies<float>(), std::placeholders::_1, 1.0/minLatency));
454 machine->numa.baseLatency = 1.0; // latencies still do not have any units in hwloc-2.x
455 machine->numa.maxRelativeLatency = maxLatency/minLatency;
457 #else // GMX_HWLOC_API_VERSION_IS_2XX == false, hwloc api is 1.x.x
458 int depth = hwloc_get_type_depth(topo, HWLOC_OBJ_NUMANODE);
459 const struct hwloc_distances_s * dist = hwloc_get_whole_distance_matrix_by_depth(topo, depth);
460 if (dist != nullptr && dist->nbobjs == hwlocNumaNodes.size())
462 machine->numa.baseLatency = dist->latency_base;
463 machine->numa.maxRelativeLatency = dist->latency_max;
464 machine->numa.relativeLatency.resize(dist->nbobjs);
465 for (std::size_t i = 0; i < dist->nbobjs; i++)
467 machine->numa.relativeLatency[i].resize(dist->nbobjs);
468 for (std::size_t j = 0; j < dist->nbobjs; j++)
470 machine->numa.relativeLatency[i][j] = dist->latency[i*dist->nbobjs+j];
478 #endif // end GMX_HWLOC_API_VERSION_IS_2XX == false
481 // Deals with the case of no numa nodes found.
482 #if GMX_HWLOC_API_VERSION_IS_2XX
483 // If the hwloc version is 2.x.x, and there is no numa node, something went wrong
489 // No numa nodes found. Use the entire machine as a numa node.
490 // Note that this should only be the case with hwloc api v 1.x.x,
491 // a numa node is assigned to the machine by default in v 2.x.x
492 const hwloc_obj*const hwlocMachine = hwloc_get_next_obj_by_type(topo, HWLOC_OBJ_MACHINE, nullptr);
494 if (hwlocMachine != nullptr)
496 machine->numa.nodes.resize(1);
497 machine->numa.nodes[0].id = 0;
498 machine->numa.nodes[0].memory = hwlocMachine->memory.total_memory;
499 machine->numa.baseLatency = 10;
500 machine->numa.maxRelativeLatency = 1;
501 machine->numa.relativeLatency = { { 1.0 } };
503 for (int i = 0; i < machine->logicalProcessorCount; i++)
505 machine->numa.nodes[0].logicalProcessorId.push_back(i);
507 for (auto &l : machine->logicalProcessors)
511 for (auto &s : machine->sockets)
513 for (auto &c : s.cores)
524 #endif // end if not GMX_HWLOC_API_VERSION_IS_2XX
527 machine->numa.nodes.clear();
532 /*! \brief Read PCI device information from hwloc topology
534 * \param topo hwloc topology handle that has been initialized and loaded
535 * \param machine Pointer to the machine structure in the HardwareTopology
536 * class, where PCI device information will be filled.
538 * \return If any devices were found
541 parseHwLocDevices(hwloc_topology_t topo,
542 HardwareTopology::Machine * machine)
544 const hwloc_obj * root = hwloc_get_root_obj(topo);
545 std::vector<const hwloc_obj*> pcidevs = getHwLocDescendantsByType(topo, root, HWLOC_OBJ_PCI_DEVICE);
547 for (auto &p : pcidevs)
549 #if GMX_HWLOC_API_VERSION_IS_2XX
550 const hwloc_obj * ancestor = nullptr;
551 // Numa nodes not directly part of tree. Walk up the tree until we find an ancestor with a numa node
552 hwloc_obj_t parent = p->parent;
553 while (parent && !parent->memory_arity)
555 parent = parent->parent;
559 ancestor = parent->memory_first_child;
561 #else // GMX_HWLOC_API_VERSION_IS_2XX = false, api v 1.x.x
562 // numa nodes are normal part of tree, can use hwloc ancestor function
563 const hwloc_obj * const ancestor = hwloc_get_ancestor_obj_by_type(topo, HWLOC_OBJ_NUMANODE,
564 const_cast<hwloc_obj_t>(p));
565 #endif // end if GMX_HWLOC_API_VERSION_IS_2XX
567 if (ancestor != nullptr)
569 numaId = ancestor->logical_index;
573 // If we only have a single numa node we belong to it, otherwise set it to -1 (unknown)
574 numaId = (machine->numa.nodes.size() == 1) ? 0 : -1;
577 GMX_RELEASE_ASSERT(p->attr, "Attributes should not be NULL for hwloc PCI object");
579 machine->devices.push_back( {
580 p->attr->pcidev.vendor_id,
581 p->attr->pcidev.device_id,
582 p->attr->pcidev.class_id,
583 p->attr->pcidev.domain,
586 p->attr->pcidev.func,
590 return !pcidevs.empty();
594 parseHwLoc(HardwareTopology::Machine * machine,
595 HardwareTopology::SupportLevel * supportLevel,
598 hwloc_topology_t topo;
600 // Initialize a hwloc object, set flags to request IO device information too,
601 // try to load the topology, and get the root object. If either step fails,
602 // return that we do not have any support at all from hwloc.
603 if (hwloc_topology_init(&topo) != 0)
605 hwloc_topology_destroy(topo);
606 return; // SupportLevel::None.
609 // Flags to look for io devices
610 #if GMX_HWLOC_API_VERSION_IS_2XX
611 hwloc_topology_set_io_types_filter(topo, HWLOC_TYPE_FILTER_KEEP_IMPORTANT);
613 hwloc_topology_set_flags(topo, HWLOC_TOPOLOGY_FLAG_IO_DEVICES);
616 if (hwloc_topology_load(topo) != 0 || hwloc_get_root_obj(topo) == nullptr)
618 hwloc_topology_destroy(topo);
619 return; // SupportLevel::None.
622 // If we get here, we can get a valid root object for the topology
623 *isThisSystem = hwloc_topology_is_thissystem(topo) != 0;
625 // Parse basic information about sockets, cores, and hardware threads
626 if (parseHwLocSocketsCoresThreads(topo, machine))
628 *supportLevel = HardwareTopology::SupportLevel::Basic;
632 hwloc_topology_destroy(topo);
633 return; // SupportLevel::None.
636 // Get information about cache and numa nodes
637 if (parseHwLocCache(topo, machine) && parseHwLocNuma(topo, machine))
639 *supportLevel = HardwareTopology::SupportLevel::Full;
643 hwloc_topology_destroy(topo);
644 return; // SupportLevel::Basic.
648 if (parseHwLocDevices(topo, machine))
650 *supportLevel = HardwareTopology::SupportLevel::FullWithDevices;
653 hwloc_topology_destroy(topo);
654 // SupportLevel::Full or SupportLevel::FullWithDevices.
659 /*! \brief Try to detect the number of logical processors.
661 * \return The number of hardware processing units, or 0 if it fails.
664 detectLogicalProcessorCount()
669 #if GMX_NATIVE_WINDOWS
672 GetSystemInfo( &sysinfo );
673 count = sysinfo.dwNumberOfProcessors;
674 #elif defined(HAVE_SYSCONF) && defined(_SC_NPROCESSORS_ONLN)
675 // We are probably on Unix. Check if we have the argument to use before executing any calls
676 count = sysconf(_SC_NPROCESSORS_ONLN);
678 count = 0; // Neither windows nor Unix.
688 HardwareTopology HardwareTopology::detect()
690 HardwareTopology result;
693 parseHwLoc(&result.machine_, &result.supportLevel_, &result.isThisSystem_);
696 // If something went wrong in hwloc (or if it was not present) we might
697 // have more information in cpuInfo
698 if (result.supportLevel_ < SupportLevel::Basic)
700 // There might be topology information in cpuInfo
701 parseCpuInfo(&result.machine_, &result.supportLevel_);
703 // If we did not manage to get anything from either hwloc or cpuInfo, find the cpu count at least
704 if (result.supportLevel_ == SupportLevel::None)
706 // No topology information; try to detect the number of logical processors at least
707 result.machine_.logicalProcessorCount = detectLogicalProcessorCount();
708 if (result.machine_.logicalProcessorCount > 0)
710 result.supportLevel_ = SupportLevel::LogicalProcessorCount;
716 HardwareTopology::Machine::Machine()
718 logicalProcessorCount = 0;
719 numa.baseLatency = 0.0;
720 numa.maxRelativeLatency = 0.0;
724 HardwareTopology::HardwareTopology()
725 : supportLevel_(SupportLevel::None),
731 HardwareTopology::HardwareTopology(int logicalProcessorCount)
732 : supportLevel_(SupportLevel::None),
736 if (logicalProcessorCount > 0)
738 machine_.logicalProcessorCount = logicalProcessorCount;
739 supportLevel_ = SupportLevel::LogicalProcessorCount;
743 int HardwareTopology::numberOfCores() const
745 if (supportLevel() >= SupportLevel::Basic)
747 // We assume all sockets have the same number of cores as socket 0.
748 // Since topology information is present, we can assume there is at least one socket.
749 return machine().sockets.size() * machine().sockets[0].cores.size();
751 else if (supportLevel() >= SupportLevel::LogicalProcessorCount)
753 return machine().logicalProcessorCount;